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- ID:
- ivo://CDS.VizieR/J/ApJ/454/151
- Title:
- OB Associations of the Northern Milky Way
- Short Name:
- J/ApJ/454/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the massive star content of Milky Way clusters and OB associations in order to answer three questions: (1) How coeval is star formation? (2) How constant is the initial mass function (IMF)? (3) What is the progenitor mass of Wolf-Rayet stars? Our sample includes NGC 6823/Vul OB1, NGC 6871/Cyg OB3, Berkeley 86/Cyg OB1, NGC 6913/Cyg OB1, NGC 7235, NGC 7380/Cep OB1, Cep OB5, IC 1805/Cas OB6, NGC 1893/Aur OB2, and NGC 2244/Mon OB2. Large-field CCD imaging and multiobject, fiber spectroscopy has resulted in UBV photometry for >10,000 stars and new spectral types for ~200 stars. These data are used to redetermine distances and reddenings for these regions and to help exclude probable nonmembers in constructing the H-R diagrams. We reanalyze comparable data previously published on Cyg OB2, Tr 14/16, and NGC 6611 and use all of these to paint a picture of star formation and to measure the IMFs. We find the following: (1) Most of the massive stars are born during a period Delta(Tau) < 3 Myr in each association. Some star formation has clearly preceded this event, as evidenced by the occasional presence of evolved (Tau ~ 10 Myr) 15 Msun stars despite a typical age Tau ~ 2 Myr for the more massive population. However, all these regions also show evidence of 5-10 Msun pre-main-sequence stars (Tau < 1 Myr), demonstrating that some star formation at lower masses does continue for at least 1 Myr after the formation of high-mass stars. (2) There is no statistically significant difference in IMF slopes among these clusters, and the average value is found to be Gamma = -1.1 +/- 0.1 for stars with masses > 7 Msun. A comparison with similarly studied OB associations in the Magellanic Clouds reveals no difference in IMF slope, and hence we conclude that star formation of massive stars in clusters proceeds independently of metallicity, at least between z = 0.02 and z = 0.002. The masses of the highest mass stars are approximately equal in the Milky Way, LMC, and SMC associations, contrary to the expectation that this value should vary by a factor of 3 over this metallicity range. We conclude that radiation pressure on grains must not limit the mass of the highest mass star that can form, in accord with the suggestion of Wolfire & Cassinelli that the mere existence of massive stars suggests that shocks or other mechanisms have disrupted grains in star-forming events. (3) The four Wolf-Rayet stars in our sample have come from stars more massive than 40 Msun; one WC star and one late-type WN star each appear to have come from very massive (~100 Msun) progenitors.
- ID:
- ivo://CDS.VizieR/J/ApJS/2/389
- Title:
- Observations of O and B stars
- Short Name:
- J/ApJS/2/389
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog of O and B stars contains magnitudes, colors, spectral types and polarization for 1259 stars. In addition to observations, the catalogue contains the derived absorption and distance modulus. A photoelectric photometer attached to the 82-inch (2m) reflector of the McDonald Observatory was used for the polarization observations. The photometric UBV observations were made over a period of 4 years with the 13-inch (33cm) and the 82-inch telescopes at McDonald. The spectroscopic classification was made with a new camera installed on the Cassegrain spectrograph, with a dispersion of 86{AA}/mm at H{delta}.
- ID:
- ivo://CDS.VizieR/J/PAZh/30/37
- Title:
- Observations of supernovae in 1997-1999
- Short Name:
- J/PAZh/30/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric observations of 15 supernovae discovered in the period 1997-1999 are presented.
- ID:
- ivo://CDS.VizieR/II/146
- Title:
- Observations of the Ap Star HR 1217 from 1980-86
- Short Name:
- II/146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This file contains magnitudes from nearly 50,000 40 second observations of the rapidly oscillating Ap star HR 1217 obtained during nearly 600 hours of observation at various observatories from 1980 to 1986. Most of the observations were made through Johnson B filters, but some were made through other filters. All data in this file were included in a paper entitled The high-overtone p-mode spectrum of the rapidly oscillating Ap star HR 1217 (HD 24712) by Kurtz et al. (1989MNRAS.240..881K) and described in the CDS Inf. Bull. (Kurtz 1989). Much of the information published in Kurtz et al. (1989) had been gathered from previously published literature, and some had been obtained by a team established for that paper. Each record holds one observation with the Heliocentric Julian Date given to 5 decimal accuracy and the magnitude given to 4 decimal accuracy. The observations are grouped so that all observations from a single night from each observatory are listed together. The data published in Kurtz et al. (1989) included observations previously published as follows: Julian Dates Source of data ------------ -------------- JD2444540-2444643 Kurtz (1982MNRAS.200..807K) JD2444849-2444953 Kurtz & Seeman (1983MNRAS.205...11K) JD2445661-2445664 H. J. Wood (unpublished) JD2445690-2445693 Kurtz, Schneider & Weiss (1985MNRAS.215...77K) JD2446712-2446784 original (Kurtz et al. 1989MNRAS.240..881K)
- ID:
- ivo://CDS.VizieR/J/PAZh/26/13
- Title:
- Observations of X-ray binary A0535+26/V725 Tau
- Short Name:
- J/PAZh/26/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBV photoelectric observations of A0535+26/V725 Tau are obtained at Crimean Station of SAI in 1980 and 1988-1998.
- ID:
- ivo://CDS.VizieR/J/AJ/159/267
- Title:
- Observations & radial velocity of HATS-71b
- Short Name:
- J/AJ/159/267
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HATS-71b, a transiting gas giant planet on a P=3.7955day orbit around a G=15.35mag M3 dwarf star. HATS-71 is the coolest M dwarf star known to host a hot Jupiter. The loss of light during transits is 4.7%, more than in any other confirmed transiting planet system. The planet was identified as a candidate by the ground-based HATSouth transit survey. It was confirmed using ground-based photometry, spectroscopy, and imaging, as well as space-based photometry from the NASA Transiting Exoplanet Survey Satellite mission (TIC234523599). Combining all of these data, and utilizing Gaia DR2, we find that the planet has a radius of 1.024{+/-}0.018R_J_ and mass of 0.37{+/-}0.24M_J_ (95% confidence upper limit of <0.80M_J_), while the star has a mass of 0.4861{+/-}0.0060M_{sun}_ and a radius of 0.4783{+/-}0.0060R_{sun}_.
- ID:
- ivo://CDS.VizieR/J/A+A/538/A142
- Title:
- OB stars in NGC 6334 and NGC 6357
- Short Name:
- J/A+A/538/A142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Star-forming complexes are large structures exhibiting massive star-formation at different stages of evolution, from dense cores to well-developed HII regions. They are very interesting for the study of the formation and evolution of stars. NGC 6334 and NGC 6357 are two active and relatively nearby star-forming complexes. From the extinction map and the sub-mm cold dust emission, and because they have similar velocities, these regions are most likely connected. However, located in the direction of the Galactic center their radial velocity is not representative of their distance. An alternative is then to determine the distance of NGC 6334 and NGC 6357 from their stellar content. Our aim is to perform a census of O-B3 ionising stars in NGC 6334 and NGC 6357, to determine the extinction coefficient, and the distance of both regions. A census of O-B3 stars is an essential basis for estimating the statistical lifetime of the earliest massive star-forming phases.
1049. OGLE LMC BVI photometry
- ID:
- ivo://CDS.VizieR/J/AcA/50/307
- Title:
- OGLE LMC BVI photometry
- Short Name:
- J/AcA/50/307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the BVI photometric maps of the Large Magellanic Cloud. They contain BVI photometry and astrometry of more than 7 million stars from the central parts of the LMC. The data were collected during the second phase of the OGLE microlensing project. We discuss the accuracy of the data and present color-magnitude diagrams of all 26 fields observed by OGLE in the LMC. The BVI maps of the LMC are accessible electronically for the astronomical community from the OGLE Internet archive.
1050. OGLE RR Lyrae in LMC
- ID:
- ivo://CDS.VizieR/J/AcA/53/93
- Title:
- OGLE RR Lyrae in LMC
- Short Name:
- J/AcA/53/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalog of RR Lyr stars discovered in a 4.5 square degrees area in the central parts of the Large Magellanic Cloud (LMC). Presented sample contains 7612 objects, including 5455 fundamental mode pulsators (RRab), 1655 first-overtone (RRc), 272 second-overtone (RRe) and 230 double-mode RR Lyr stars (RRd). Additionally we attach alist of several dozen other short-period pulsating variables. The catalog data include astrometry, periods, BVI photometry, amplitudes, and parameters of the Fourier decomposition of the I-band light curve of each object. We provide a list of six LMC star clusters which contain RR Lyr stars. The richest cluster, NGC 1835, hosts 84 RR Lyr variables. The period distribution of these stars suggests that NGC1835 shares features of Oosterhoff type I and type II groups. All presented data, including individual BVI observations and finding charts are available from the OGLE Internet archive at ftp://sirius.astrouw.edu.pl/ogle/ogle2/var_stars/lmc/rrlyr
